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Old 02-12-2015, 10:07 AM   #59 (permalink)
oldtamiyaphile
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Quote:
Originally Posted by freebeard View Post
I understand that regen requires AC which requires FOC which gets complicated. Maybe a 2nd DC motor mounted in reverse and an A-B switch?
Can I do regen on a DC drive motor, say a forklift one?

R/C DC motors do regen, my understanding is that the problem with larger motors is it's difficult to deal with back EMF, not really sure. I have plenty of electric motor experience, but only at smaller scales.

I don't think R/C brushless motors do regen, at least not the big ones. It's not really an issue for their intended use as aircraft wouldn't gain much from regen.

I'm going to start with a basic trailer, get it registered, then add a diff and experiment from there. I'll need something like a Toyota Hilux diff with the lowest ratio I can find.

Integrating a DIY hybrid into a manual trans car is difficult from a driving point of view, but I've got a basic method worked out. Two modes, low speed and high speed. Low speed is for creeping in traffic etc. Works engine on or off, gear in neutral. Motor controller is connected to the DBW throttle and you simply accelerate and the motor accelerates. Cuts off at say 8km/h where you're likely to be going for second gear. I would also like to use this for bump starting to spare my starter motor.

High speed mode, intended for increasing glide distances, waits for car to be in neutral and engine off, then the accelerator controls the electric motor rather than the ICE.

It's a pretty narrow operating window, but it should be all I need and reduce the cost/ amount of batteries required. Anything more seems like it will make changing gears too difficult, and may not respond correctly to an emergency brake input (like adding a gear change delay). The trailer roof should have space for 2-300W of solar panels and the tow vehicle already has a 100W panel that isn't being used to the full.

ROI, I'm not a hypermiler for the monetary gain, but tax law (AU) lets me claim fuel based on distance traveled at the EPA rating, so it's a bit like double dipping, $$ saved at the pump and an 'additional' tax break. It's also a lower stress way to drive, it doesn't really matter if someone tailgates and rear ends the trailer.

Looks like I'll need 12kWh of batteries for a day's driving, that's about 10 lead acid batteries, but of course ideally, something lighter. The solar panels will provide a realistic 550Wh while parked during the day between commutes.
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Last edited by oldtamiyaphile; 02-12-2015 at 10:17 AM..
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